Publications

Published: July 1998

MMR Vaccine, Bowel Disease and Autism

Prescriber Update 16: 41–42
July 1998

Dr Osman Mansoor, Public Health Group, Ministry of Health

A small case series has found a temporal association between autism associated with bowel disease and
MMR vaccine. The evidence does not suggest that the vaccine causes autism. Public perception of risk
can affect the uptake of vaccines and lead to an increase in vaccine-preventable disease. The Ministry
continues to recommend immunisation, and does not consider autism a risk factor of MMR vaccine.

An 'early report' implicated measles-mumps-rubella (MMR) vaccine as a cause of autism.1
The report described 11 boys and one girl with variable bowel abnormalities and serious developmental
regression (autism in nine cases). Symptoms appeared one day to two months after immunisation. The
hypothesis put forward by the authors is that MMR vaccine causes inflammation or dysfunction of the
intestine, increasing the absorption of non-permeable peptides, which in turn can cause serious
developmental disorders.

Doubt cast on alleged link

The accompanying commentary cast doubt on the alleged link.2 The case series
was subject to both selection and recall bias, the pathological findings were non-specific, there was no
clear case definition and confirmatory virological studies had not been completed. The commentary also noted
that although the authors had found measles virus in inflammatory bowel disease, the investigations of other
researchers were negative. Indeed, the same edition of the Lancet included another study which failed
to find measles virus genome in inflammatory bowel disease even though the researchers used a highly
sensitive assay.

Unbalanced media coverage can have serious consequences

Last year the same authors claimed that MMR vaccine caused Crohn’s disease. This also received widespread
media coverage despite evidence not supporting the claim. Since then, accumulating evidence against the link3
has been ignored by the media. The consequent decline in confidence in MMR vaccine has affected coverage in
the United Kingdom.4

A recent editorial warns of the danger of repeating the harm caused in the United Kingdom from media
reports in the 1970s about pertussis vaccine causing brain damage.5 As a result
of the decline in pertussis immunisation, there were three major epidemics over 12 years causing over
300,000 notifications and at least 70 deaths.

No evidence to suggest MMR vaccine causes autism

On 23 March 1998, the British Medical Research Council held a meeting of experts who concluded that the
available evidence does not indicate a link between measles, measles vaccine or MMR immunisation and either
Crohn’s disease or autism. Two other studies have failed to show any association.6,7

The Ministry of Health also considers there is no evidence to suggest that there is a risk of autism from
MMR vaccine. Information contained in the Immunisation Choices booklet still represents an accurate
description of the risks of immunisation compared to the disease. High immunisation coverage is critical to
disease control, especially at the tail-end of a measles epidemic that was limited through immunisation.